May 7 2009, 07:34 PM
It's a reasonable idea that mercury has water ice in shadowed craters at it's poles, and that meteorites containing organics rain down on the planet the same as with earth. So there's probably some organics mixed in with the ice- and the ice has probably been subjected to impacts, radiation, and possibly even warming by vulcanism. So how would mercury organics compare to those found in ices on bodies in the outer solar system? Edit: A search of the web hasn't turned up much, and I wonder if organic materials would be processed differently, given that mercury is a dense rocky world near the sun, as opposed to an icy world far from it.
May 8 2009, 02:23 AM
Well....I'll take a wild guess:
Closer to the sun, there would be more irradiation of the ices causing more oxygen radicals that could run around and do things. So I'd suppose more organic materials would be in the oxidized form.
The temperature difference would also remove kinetic barriers to further reaction. So many of the feebler molecules and species that are stable in the outer solar system worlds might break down to other products. (I'm thinking of unstable polyynes - they might not last long at higher inner solar system temperatures).
Also with the warmer temperatures, more hydrolysis might also occur. Things like dicarbodimides, amidines, imines and kin might break down to the corresponding carbonyl derivatives (ureas, carboxylic acids, ketones, aldehydes). Large funky polymers might also hydrolyze out to smaller units. (I'm thinking of hydrolysis experiments with tholins that liberate amino acids)
Finally, the rocky worlds would have metals and metal salts that could mix it up with any organics and help catalyze further reactions (also via pH modification of the medium). The outer ice worlds are mostly water ice, thus metal-poor.
For either (putative) Mercury organics or outer solar system organics, the really interesting stuff would require sophisticated in situ analysis or sample return to figure out structures. (complex rings, amino acids etc.)
May 8 2009, 10:07 AM
I thought that the temperatures in the 'craters of eternal darkness' were similar to those in the outer solar system, IE around 100 deg K? Still a comparison between (putative) mercury organics and the outer solar system bodies organic would be interesting, particularly the effect of abundant metals nearby and higher radiation. A phoenix type lander to one of the poles would be fascinating, but mercury seems as difficult to get to as the outer planets in terms of the energy needed. I hope it's done one day though, mercury is turning out to be a lot more interesting than the baked out rock I was told about in school!
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